He's a former president of The Rockefeller Foundation in the US, former chief scientist of the Department for International Development in the UK, and authored 'One Billion Hungry: Can We Feed the World?'

Sir Gordon Conway started his career as a government entomologist in North Borneo working with the cocoa industry.

"When I arrived there all the cocoa was stripped of its leaves because there were huge pest outbreaks and I discovered the growers of the cocoa were spraying it with all kinds of insecticides like DDT, chlordane BHC and so on," he said.

"I decided they were killing the natural enemies of the pest with the pesticides, so I said they had to stop spraying and they said 'You don't know what you're talking about, you're only 22-years-old and straight out of university'.

"But I got my director of agriculture to agree that was the problem, so we banned all spraying of pesticides on cocoa and the natural enemies came alive and controlled all the pests, and it lasted for 30 years."

Sir Gordon Conway is the Professor of International Development and director of the Agriculture for Impact, a program funded by Bill and Melinda Gates, at the Imperial College in London.

He delivered the keynote address at the Borlaug 100 Summit on Wheat for Food Security in Mexico.

Sustainable intensification

Sir Gordon Conway says the world's food production needs to be increased by 70 to 100 per cent by 2050.

He says two major challenges need to be met to achieve that goal.

"One is that we have to increase food production but on the same amount of land with the same amount of water because we've got limited amounts of good quality land and water," he said.

"The second is that it has to be done sustainably, that means we have to use fertilisers and pesticides more prudently not like the way we used pesticides in Borneo years ago.

Sir Gordon Conway says the world also needs to increase its natural capital.

"That means we've got to improve the water retaining capacity of the soils for example, or build up these natural enemies I was using in Borneo, and then we've also got to make this production more resilient," he said.

"So, that's a tall order. It's what we call sustainable intensification, we've got to intensify and make it more sustainable.

"We're looking for multiple benefits and we don't yet really know how to go about doing it, you can do it on a small scale but doing it on a big scale is really a big challenge.

"It's not too difficult to intensify, there are ways you can do that.

"For example if you apply more fertiliser you can get bigger yields, so we know how to do that, but the problem is when you apply more fertiliser the fertiliser pollutes, washes off and it produces greenhouse gases.

He says one solution is to make sure that the fertiliser is better targeted.

"In Africa they're using the top of Coca Cola or Pepsi Cola bottles, the little cap at the top and putting the fertiliser in that and then putting that fertiliser in a hole where you're going to plant the seed of the maize," he said.

"So you only apply 11 kilos of fertiliser per hectare, instead of hundreds per hectare, the fertiliser goes exactly where it's needed for the plant and it doesn't spread all over the field.

"That's what we mean by a sustainable intensification but you could do it in lots of other ways too, but it takes ingenuity and it'll take a lot of really good research to make that happen."

Reducing meat consumption

With our global appetite for meat rising that means a greater demand for grain.

"It's a huge problem because so many countries including places like China, India, Brazil and Mexico their diets are changing, they're all tending to eat diets similar to the ones we eat in Europe and Australia and America," he said.

Those diets consist of higher proportions of dairy products like milk, cheese and butter, and more meat including poultry, pork, beef and lamb.

But Sir Gordon Conway says that level of livestock production requires a lot of grain.

"I mean very crudely you need about seven kilos of grain for every kilo of meat you produce so as the consumption of livestock goes up the amount of grain we have to produce just to feed the livestock is huge," he said.

"Well, some people say we should all become vegetarians and that would probably solve the problem but I don't see it happening on a big scale.

They look like prawns, they walk like prawns, they talk like prawns, you can't tell they're any different from prawn but they're made out of soya bean.

Sir Gordon Conway, Professor of International Development, Imperial College, London

When Sir Gordon Conway spoke recently at the China Agricultural University he says there wasn't one vegetarian among the hundreds of students in the audience.

"One possibility, and I think we need to be thinking very seriously about this, is that you can start to produce livestock products by taking vegetables such as soya bean and you could produce something out of it that looks like meat," he said.

He says this is already happening in parts of Asia.

"You can go to Northern Thailand and you can buy some prawns and they look like prawns, they walk like prawns, they talk like prawns, you can't tell they're any different from prawn but they're made out of soya bean," he said.

"It's interesting that Bill Gates thinks that this is really part of the solution to the problem and is putting money into developing this kind of activity so I think that's going to be important.

"I think of all us are going to have to reduce the amount of meat we consume."

Call for genetic modification

Sir Gordon Conway believes that GM crops are needed but only in the longer term and for specific pests and diseases.

Such as potato blight he says. The potato disease had a devastating impact on Ireland during the mid 19th century.

"My grandfather was born in 1850 at the end of the famine, that famine was caused by potato blight, a million people in Ireland died, it was appalling," he said.

"What they've now got is genetic modification of a potato that's resistant to potato blight, because potato blight has come back in Britain, there are farms in Britain that lose their whole potato crop because of potato blight.

"We've now got potatoes that are resistant, they're exactly the same potatoes as they were before, they've just got a gene that gives resistance to potato blight.

"They taste the same, they look the same, everything else is exactly the same except they've got that gene in them, so we're going to need those increasingly into the future and that's part of food security.

"But the bulk of science that's going into food security for the next 10 to 15 years is going to be conventional."

He says that Africa's food security will largely depend on conventional methods for the next 10 to 20 years.

But he says while that could be possible, with the amount of crop damage caused by pests and diseases GM technology will be needed.

"We know about the human disease like HIV and AIDS, TB and malaria but there are also plant diseases which are appalling like black sigatoka on bananas, like yellow stripe on wheat, and striga a terrible weed," he said.

Farmers can wake up in the morning and see the whole of their crop has been destroyed, and these are very difficult to control by conventional means so we're going to have to use GM techniques to control those pests.

"Farmers can wake up in the morning and see the whole of their crop has been destroyed, and these are very difficult to control by conventional means so we're going to have to use GM techniques to control those pests."

"Then into the future we need better drought tolerance especially in Africa, one of the consequences of climate change is going to be increasing drought so we need better drought tolerance.

"We're going to get a lot of it by conventional means but we're actually going to need new kinds of genes."

One such gene is the chaperone gene which he says allows maize plants to recover from drought.

"That is now being inserted into maize by genetic modification and is being tried out in the United States and they're going to give that to plant breeders," he said.

Sir Gordon Conway says there would be enormous benefits if cereals could fix their nitrogen the way legumes do.

"If you grow a pea or a bean that plant has got little nodules on its roots that contain bacteria that fixes the nitrogen in the atmosphere, so it gets all its nitrogen from the atmosphere," he said.

"We'd love it if wheat and maize and so on could do the same, we've been trying to do this for 30 to 40 years without success but now we understand how the nitrogen fixing nodules on legumes how they evolved, what was the genetic basis for that to happen.

"Because we now know that, and it's only happened in the last few years, there's a much greater chance that we can get to nitrogen fixation.

"It will inevitably mean genetic modification, you'd have to insert new genes, but the prize would be enormous."

He expects that won't happen though for another 15 to 20 years.

Tolerance for technology

The acceptance of genetically modified crops varies from country to country.

"Many European countries are very much against, many other countries are in favour, the United States are growing huge amounts of genetically modified food, South America is growing a lot," he said.

Sir Gordon Conway says people's tolerance for the technology depends on how they see the world.

"In Britain it's beginning to shift because people are understanding that we've got huge problems to face over the next 30 to 40 years," he said.

"We've got an energy crisis, a water crisis, all kinds of crises including a food crisis into the future so the issue is if we're going to deal with all these crises we need all the tools we can get.

Sir Gordon Conway is on The World Food Prize's Council of Advisors. He presented the Dr. Norman E. Borlaug Medallion to CIMMYT at the Borlaug 100 Summit.

Sir Gordon Conway is on The World Food Prize's Council of Advisors. He presented the Dr. Norman E. Borlaug Medallion to CIMMYT at the Borlaug 100 Summit.

Kim Honan

"Just to be against something, which is what's happening at the moment, against nuclear power, against fracking, against windmills, against GM, against all kind of things that people are against.

But he says people are realising they can't against everything.

"You could lead a comfortable middle-class life, which is what many of the anti-GM people do, but you have to be aware that there are these huge threats around you," he said.

"Climate change the way it's going is going to create a world that is absolutely appalling for all of us in terms of the stresses and shocks that we're going to suffer from.

"We've got new technologies and we can make them work, and I think as people begin to understand them they'll be more tolerant of technologies and of course GM crops are shown to be safe, there's no evidence that they cause harm."